Non-bioabsorbable fibers are known in the art. However, in the manufacture of sutures one important characteristic of a suture is the amount of effort typically required to straighten the suture upon its removal from the package in order to ready the suture for use. This effort appears to be related to the "strain energy" of the suture, i.e., the integration of the stress-strain curve for the suture measured in kilogram-mm, and is equivalent to the work expended in elongating the monofilament by a specified percentage of its original length. As the strain energy of a given size of suture decreases so, too, does the amount of effort required to straighten the suture prior to use. A decrease in strain energy also appears to relate to the perceived flexibility of the suture, another important characteristic.
Another important characteristic of a suture is its ability to retain a knot. In general, a suture exhibiting greater knot security is preferred to one exhibiting a lesser degree of knot security. Similarly, a suture must exhibit favorable straight tensile strength, loop strength and knot strength.
A further important consideration in the manufacture and use of sutures is that the physical properties of the suture should not change significantly during use. By way of example, under the tension of a surgeon's knot used for wound closure, a suture may undergo stretching which will cause the suture to stretch or elongate, a phenomenon referred to herein as "creep".
Therefore, it would be advantageous to provide a non-bioabsorbable suture which exhibits favorable physical properties as well as a high degree of physical stability, including resistance to creep.